Motion picture projecting apparatus



I. H. CRABTREE MOTION PICTURE PROJEGTING APPARATUS Filed Feb. 13, 1951 lNVENTOR gem H (#45 TREE ATTORNEY Patented Dec. 25, 1934 1,985,629

UNITED. STATES PATENT OFFICE MOTION PICTURE PROJECTIN G APPARATUS Ivory H. Crabtree, Toppenish, Wash.

. Application February 13, 1931, Serial No. 515,486

1 Claim. (Cl. 88-17) This invention relates to improvements in picthe top wall of the housing and it is fed at the ture projecting machines such as are now in genspeed needed by a driven sprocket 5, against eral use for the showing of motion pictures, and which the strip is held by an idler roll 6. The'film the improvement deals generally with the cooling strip is held properly in place for advancement,

5 of that part of the machine that becomes excesacross the aperture '7 of the front wall, or plate 8 5 I sively. heated by the light beam used for the proof the film trap assembly, by a gate 9 and it is jection of the picture. advanced intermittently by means ofa sprocket It is the principal object of this invention to wheel 10 which is intermittently driven by the overcome the undesirable effects of heat from. usual Geneva gearsand against which the film is 10 the projecting light beam and damage done to held by a roll 12. After leaving the roll 12, the 10 the projection apparatus, and to thus insure confilm strip is guided by rolls 13+ and 14 and driven tinned accuracy in the projection, by use of a film roll 15 through a slot 16 in the bottom wall of trap assembly for the projector which is designed the housing 1 and may be then wound onto a reel to be kept cool by circulation of a cooling medium for rewinding.

' 15 within it, such as water; air, or any other suitable In so far as the film feeding, winding and adis cooling fluid. vancing devices are concerned, they may be oi. More specifically stated, the present invention the usual or any preferred construction and form resides in the provision of a jacketed front or wall no part of the present invention, and the plate for the circu at on o a co g medium within or wall 8 in which is embodied the present in-- a go the wall and about the aperture through which vention is designed so that it'maybe applied to the light beam is proj ct d d oss which the already existing machines, and will not necessipicture film is moved. tate any change in the location or mode of opera It is also an object of the invention to provide tion of these parts as they already exist; the a jacketed iront of the above character that may present assembly simply replacing the uncooled be easily and readily applied to machines now in assembly of the machine as heretofore used. 25

use without requiring any alteration in the malhe present invention resides in the means for chines as they now exist, except the removal of cooling the assembly, and for this purpose the the present, uncooled front. wall plate 8 is formed about the usual aperture 7 Other objects of the invention reside in the with a jacket or housing 18 integral with the 0 various details of construction, and in the combiplate and forming a channel 19 entirely about I nation of parts, and mode of operation, as will the aperture, as shown best in Figure 2, for the hereinafter be fully described. circulation therein of a cooling medium, which In accomplishing these and other objects of the preferably would be water, but which might be invention, I have provided'the improved details air, oil or any other fluid medium suitable for of construction, the preferred forms of which are cooling. This medium, introduced by gravity 3 illustrated in the accompanying drawing, where= flow or pressure otherwise produced, enters in through a supply pipe 20 and leaves by way of Fig. 1 is avertical, sectional view of a portion or pipe 21; these pipes being threaded onto opena standard type of motion picture projecting maings' provided therefor in the side wall of the e chine equipped with a film trap assembly con= jacket.

structed and applied according to the present In the present instance, the jacket 18 is open invention. forwardly of the aperture and is formed with a V Fig.2 is an elevation of the film trap assembly, guideway 24 for the usual fire shutter 25, and

the shutter, the dowser and retaining plate being with another guideway 26 for a dowser 27 used removed for better illustration. to out off the light beam for a changeover opera- 45 Fig. 3 is a cross sectional view taken substan= tion. A cover plate 28 is fitted over these parts, tially on theline 3-3 in Figure l. as in Figure 3,-and this is provided with an aper- I Referring more in detail to the drawing-- ture 29 alined with aperture 7 for passage of the 1 designates generally that part of a motion light beam.

picture projecting machine containing the film The special advantages incident to the use of 50 feeding and advancing mechanism whereby the this device are that it does away with the usual, film strip is intermittently advanced across the inefllcient cooling plates and effectively cools that path of the light beam. As shown in Figure 1, part of the machine which ordinarily becomes the film strip 2 passes intothe housing from a excessively heated by the light beam, thereby to storage reel designated at 3, through a slot 4 in eliminating the cause of the plate warping out shape and thliS causing interference with the operation of parts associated therewith. It o'vercomes the distortion of pictures by reason of any curvature of the film caused by its being drawn across a guiding surface that has been warped by heat. Furthermore, it makes possible the easy threading of the film without danger of the operator 1 ing burned in doing this.

An impor nt feature of the construction resides in the tact that the fire shutter is set out forwardly of the film and the water jacket placed back of it. This arrangement avoids overheating of the utter even when the light beam is on it for a .ing time. The fact that it is farther removed Lem the film strip and kept cool in addition, removes any possibility of fire caused by shutter overheating, which is often the case in the old style machines. In the usual constructions, should the hand dowser be left open and eeaeaa fullyup to speed and the dowser automatically closed by means such as those set forth in in co-pendin'g application, Serial Number 399,949, filed October 16, 1929, entitled Changeover mechanism for motion picture machines.

The plate may be applied to already existing machines without necessitating any change, but for machines yet to be built, it would be original equipment.

Having thus descrif" claim as new therein, Letters Patent, is:

An aperture plate for formed with an aper strip may be drawn tion at the outsi about the aperture circling the aperture u for connection with liquid into and from 1e chamber; said extension portion also bei formed at th 1: outside of the chamber with guide slots for containing shutters movable therein from and, across the aperture.

cl my invention, what I and desire to secure by motion picture machines e across whiclzi a film having an integral portending from the plate mad with a chamber en- IVORY ClitABTREE. 

